Printed Circuit Board Assembly & PCB Design SMT Electronics Assembly Manufacturing Forum

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double sidded reflow problems

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#51359

double sidded reflow problems | 10 August, 2007

When running some double sided reflow boards through the Heller oven, some of the caps/ res's are falling off the bottom side of the board. I understand if the parts are too heavy they wont stay in the molten solder, but these particular parts are not the type that should be falling off. I wanted to know what other reasons could be causing this type of problem..........Can any one help me out?? Thanks..

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#51371

double sidded reflow problems | 13 August, 2007

This may sound silly to ask, but does your oven have a center board support by chance? If so is it down when running the boards through the oven?

I only ask this because we had the solenoid that operates that function (raise and lower) of the board support chain fail before and the chain would NOT go down when it was supposed to as programmed in the recepie.

Other than that Id look for anything that could cause the board to be disturbed when travling on the chains. Are they moving nice and smoothly?

Good luck!

Chris

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#51373

double sidded reflow problems | 13 August, 2007

Are the components that fall from the board solderable? Is the board solderable? Where is the solder for the components that fall from the board [eg, on the pads, on the component]?

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#51387

double sidded reflow problems | 13 August, 2007

We run double sided surface mount boards through our Heller oven without any parts falling off the bottom side unless they are too big/heavy. The trick we use is to set the bottom side temperature in the final 3 heat zones 10C-20C lower than the top side temperatures. Of course you need to profile your board to make sure the top side is getting hot enough for a good solder joint but this is working well for us.

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#51388

double sidded reflow problems | 13 August, 2007

Thanks for your input........When my guy gets in tomorrow I will pass on the info....

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#51389

double sidded reflow problems | 13 August, 2007

Glue is good....

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